Oil treatment of coal



Patented June18, 1935 UNITED "STATES PATENT OFFICE on. murmur con. Alfred 0. Wm, Beaver Dam, Wis.

No Drawing. Application January 18, 1984,

Serial No. 707.108

'IClaima.

- This invention relates to a process of treating solid fuels and more particularly to spraying coal, coke and the like with oil to render the same dustless.

Heretofore when oil has been used to treat coal, coke and the like, it has been thought necessary to use light oils of high gravity, usually '32 to 34 and a low temperature pour test. Such oils have a correspondingly low flash and buming points; about 350 F. and 400 'F., respectively. As in the present invention, oils of1this type have been sprayed on the material to be treated. In addition to light oils emulsions of oil and water have been used.

The prior practice as described above is sub-- ject to numerous and known disadvantages. One of the'most important of these is that, light oil having a large percentage of volatile constituents; is readily absorbed by the material on which it is, sprayed or evaporates therefrom. This is especially so in the case of screenings. The consequence f this characteristic is that its dust preventing and dust holding qualities are poor, and the oil which is absorbed, and remains below the surface of the coal and is wasted. Another is that coal treated with oils of the above type having low flash and burning points, is too volatile for ordinary use and is likely to flare back while being fired or to ignite due to spontaneous combustion.

The adhesive properties of light oils are poor and although generally they are suflicient when the coal being treated is dry, light oil will not adhere sufliciently to wet coal to be of any material value. When the coal dries, it is only partially coated with oil, the result being thatit must be retreated. The cost of retreating'is high for it involves not only the cost of additional oil required but also of reacreming the coal as the tumbling to which the coal is Sull iected during treatment, increass the percentage of screenings. If the coal is not screened its value is greatly reduced'so that either way faulty treating is expensive.

In the use of light oilthe further difllculty arises that in cold weather atomization is dimcult due to thickening of the oil and considering the fact that more coal is handled in'cold weather than in warm, the problem involved is important. At best coal sprayed during cold weather must be permitted to stand for several days to allow the oil to creep to completely cover the coal and it very often happens that the coal is not completely covered. Its appearance is then not uniform and is less salable due to glisttgning globules of oil interspersed with dull spo Emulsions of oil and water are also-unsatisfactory for treating coal. In cold weather such emulsions freeze in their containers, and also 6 coal which has been treated with them freezes. Coal treated with oil emulsions and stored in open bins exposed to rain loosens its coating for the reason that rain will re-emulsify the oil coating and wash it oil.

An object of the present invention is to overcome the difliculties which arise in the use ofpresent methods by using in the place of light oil a hot highly viscous oil, for more permanent treatment and to reduce degradation.

Another object is to provide a method of treat ing coal, c ke or the like to render the same dustless.

Another object is to provide a process for treating coal, coke or the like in which a greater 20' weight of coal can be treated per unit column of oil than is possible by present methods.

A further object is to provide a method 01' providing coal, coke or the like with an adhesive, substantially non-penetrating, non-evaporating, dust holding surface film of oil.

These and other objects will be apparent from the following specification. The present invention contemplates the use of a highly viscous oil, having a flash and burning point approximately that of coal, to spray over a fuel such as coal, coke and the like.

Oils are divided into two broad classes, name 1y, those with a parailine base and those with an asphalt base. Parafline base oils have a high gravity, 28 to 35 Baume at 60 F., and a relatively low viscosity. Asphalt base oils on the other hand, have a low gravity, namely, 19 to 25 Baum at 60 FL, and a relatively high viscosity. Oils of the asphalt base group having 40 a high viscosity and low gravity are used in this invention. It,has been found that oils having a gravity of 19 to 25 Baum at 60 F. and a Saybolt viscosity of 100 to 1200 at 100 F. produce the best results. While this invention as explained covers asphalt base oils having a gravity ranging from 19 to 25, it also contemplates the use of Mid-Continent and blended oils having a range of gravities from 25 to 30 Baum at 60 F. A further property that oils used should possess is a cold test of about 20 F. to 15 F. to facilitate handling at low temperatures.

Oils having the above properties will not atomize readily at ordinary temperatures. In

. factory results. The coal, coke or the like is treated by spraying it, preferably, but not necessarily, fromtwo or more angles while it passes over or through a chute, conveyor or pit at coal docks or yards.

Coal, coke or the like treated according to this'invention is given a uniform coating or film of oil which, due to the high viscosity of the oil, is substantially non-penetrating, non-evaporating and-highly adhesive. The hot oil, when applied to wet coal adheres tenaciously and sheds water, whereas cold oil adheres to wet .coal poorly. Screenings do not absorb any more of this oil than lumps. Natural temperature changes, brought about by variations in weather conditions do not have any effect as the oil is always heated to approximately the correct temperature.

The process comprising this invention produces positive economies. A wide range of cheap and reclaimed oils may beused. Less oil is required per ton of coal, coke or the like treated for the reason that none is absorbed by the fuel treated and the evaporation is practically nil. Less pump or air pressure is required to atomize the oil because when heated as above described, its viscosity is lower than cold light oil. No time is required to allow the oil to creep" on the surface of the fuel treated to completely cover it and it may therefore be delivered at once. When cold oil is-sprayed on .the above fuels an additional handling operation is required for the-reason that it must be stored while the oil is creeping. With the process of this invention the said fuel may be treated at the time of delivery.

While coal and coke have been referred to it is intended that any fuel of the same general character be included, including all grades of the same.

I claim: a

1. The process of treating solid lump fuel to render the same dustless, consisting of heating oil having a gravity of 19 to 30 Bauni at F. and a Saybolt viscosity of to 1200 at 100 F. to a spraying temperature of 100 to 250 F., and spraying the heated oil in finely atomized state on the fuel in quantities sufiicient to deposit on said fuel a thin, enveloping film of Oil;- 2. The process of treating solid lump fuel to render the same dustless. consisting of heating F. to a spraying temperature of 100 to 250 F.,

spraying the heated oil in finely atomized state on the fuel in quantities sufiicient to deposit on said fuel a thin enveloping film of said oil, and

agitating the fuel while spraying.

4. The process of treating solid lump fuel with heavy hydrocarbon oil of a viscosity too high to be sprayed in a fine mist at ordinary temperatures, consisting of heating the oil sufilcient- 1y to fluidize the same and to allow spraying, and then spraying the thus-heated oil in a finely atomized spray onto the fuel in quantity sufilcient to deposit on said fuel a thin film of said oil.

5. The process of treating solid lump fuel with asphalt base oil of a viscosity too high to be sprayed in a fine mist at ordinary temperatures, consisting of heating the oil sumciently to fluidize the, same and to allow spraying, and then spraying the thus heated oil in a finely atomized spray onto the fuel in quantity-sufiicient to deposit on said fuel a thin film of said oil.

6. The process of treating solid lump fuel with heavy hydrocarbon oil of a viscosity too high to be sprayed in a fine mist at ordinary temperatures, consisting of heating the oil sumciently to fiuidize the same and to allow spraying, and then spraying the thus heated oil in a finely atomized spray onto the fuel inquantity sufllcient to deposit on said fuel a thin enveloping "film of said oil but insufilcient to penetrate and the'penetration of said fuel by said oil being thus substantially nil.

7. The process of treating solid lump fuel with heavy hydrocarbon oil of a viscosity too high posit on said fuel a thinenveloping film of said.

oil, and agitating the fuel while spraying.

ALFRED O. VINZ. 

